randomizr (version 0.8.0)

simple_ra_probabilities: Probabilties of assignment: Simple Random Assignment

Description

Probabilties of assignment: Simple Random Assignment

Usage

simple_ra_probabilities(N, prob = NULL, prob_each = NULL, num_arms = NULL,
  condition_names = NULL, check_inputs = TRUE)

Arguments

N

The number of units. N must be a positive integer. (required)

prob

Use for a two-arm design. prob is the probability of assignment to treatment and must be a real number between 0 and 1 inclusive. (optional)

prob_each

Use for a multi-arm design in which the values of prob_each determine the probabilties of assignment to each treatment condition. prob_each must be a numeric vector giving the probability of assignment to each condition. All entries must be nonnegative real numbers between 0 and 1 inclusive and the total must sum to 1. (optional)

num_arms

The number of treatment arms. If unspecified, num_arms will be determined from the other arguments. (optional)

condition_names

A character vector giving the names of the treatment groups. If unspecified, the treatment groups will be named 0 (for control) and 1 (for treatment) in a two-arm trial and T1, T2, T3, in a multi-arm trial. An execption is a two-group design in which num_arms is set to 2, in which case the condition names are T1 and T2, as in a multi-arm trial with two arms. (optional)

check_inputs

logical. Defaults to TRUE.

Value

A matrix of probabilities of assignment

Examples

# NOT RUN {
# Two Group Designs
prob_mat <- simple_ra_probabilities(N=100)
head(prob_mat)

prob_mat <- simple_ra_probabilities(N=100, prob=0.5)
head(prob_mat)

prob_mat <- simple_ra_probabilities(N=100, prob_each = c(0.3, 0.7),
                        condition_names = c("control", "treatment"))
head(prob_mat)

# Multi-arm Designs
prob_mat <- simple_ra_probabilities(N=100, num_arms=3)
head(prob_mat)

prob_mat <- simple_ra_probabilities(N=100, prob_each=c(0.3, 0.3, 0.4))
head(prob_mat)

prob_mat <- simple_ra_probabilities(N=100, prob_each=c(0.3, 0.3, 0.4),
                        condition_names=c("control", "placebo", "treatment"))
head(prob_mat)

prob_mat <- simple_ra_probabilities(N=100, condition_names=c("control", "placebo", "treatment"))
head(prob_mat)

# }